The deployment of cellular networks, satellite networks and other wireless networks, has greatly expanded the use of mobile wireless communication devices. Whether a wireless communication device is a handheld device or a vehicle mounted device, there is an abiding interest in making the devices small so that they can be conveniently carried or accommodated in a small allocated space.
Advances, by many orders of magnitude, in the degree of integration and miniaturization of electronics over the past few decades have facilitated extreme miniaturization of transceiver electronic circuits. However, the methods and means used to miniaturize electronic circuits, cannot be applied to miniaturize antennas, because antennas operate under the principles of Maxwell's equations, which, roughly speaking, indicate that if antenna efficiency is to be preserved, the size of the antenna must be scaled according to the wavelength of the carrier frequency of the wireless signals that are to be received and/or transmitted.
Compounding the challenge of reducing antennas size, is the fact, that for many wireless communication devices, the antenna system needs to support operation at multiple frequencies, e.g., in multiple relatively wide frequency bands. The obvious expedient of using separate antennas to support separate operating frequencies, is contrary to the desire to reducing the space occupied by the antenna system.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.